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-   1st Generation Specific (1979-1985) (https://www.rx7club.com/1st-generation-specific-1979-1985-18/)
-   -   dellorto & Holley fuel pres. reg. (https://www.rx7club.com/1st-generation-specific-1979-1985-18/dellorto-holley-fuel-pres-reg-111301/)

Kouki FB 09-05-02 04:31 AM

racing beat dellorto
 
i think racing beat recommends 4.5psi of fuel pressure because if u buy a dellorto from racing beat it is modified. it is different from stock dhla dellortos. Racing Beat modified the Dellorto carburetor in several ways. The obvious modification was the addition of the two fittings to connect the tubes from the metering oil pump. Two other modifications that I am aware of are an altered emulsion tube and accelerator pump gasket. Racing Beat no longer has these replacement parts.

metalliman 09-05-02 11:45 AM

I took the float bowl cover off, the needle seems to move quite freely, no sticking or anything. Anyone know just how high the fuel level should be in the float bowl? I guess I'll try bending that tab in order to lower the fuel level in the float bowl, and see what happens.

metalliman 09-05-02 12:08 PM

I just measured the fuel level in my float bowl. It measures 1 3/8" from the bottom of the bowl. This is just after turning the key to the "run" position for 10 seconds then turning it off. Does this sound right?

SilverRocket 09-05-02 12:24 PM

I'm not sure if that's right or not, but I know the float levels have to be set precisely. I can't remember offhand what the proper levels are.... they are on that website and it's down right now lol. I made a little tool to set mine, basically a tie wrap with the 2 levels marked on it.

Could it be that your float levels are set incorrectly?

How did you set them, and to what heights?

diabolical1 09-05-02 06:28 PM

i started a thread a few months ago when i was having trouble with my Dell'Orto, and rxcetera helped me get though it all ... i just did a search because i was going to post a link to see if any of that info would help metalliman, and now i can't find it!

anyone know what might have happened?

metalliman 09-06-02 12:19 AM

I went to that website, couldn't find anything about proper float levels, maybe you could find it?

As for this missing thread, I too would like to find it, but I have no idea what happens to a lot of posts.

SilverRocket 09-06-02 12:55 AM

Here ya go...

I don't have much clue as to whether this might help your problem, but it's somewhere to start.

Did you rebuild and clean this carb (as you absolutely should have) before installing it? I'm just wondering if there is a more serious problem here.


Racing Beat recommends float levels of 15mm from the gasket in the closed position and 28mm in the wide-open position. It’s important to realize that the 15mm measurement is taken BEFORE the needle spring is compressed. These measurements provide a good compromise between the right hand turn stumbling and flooding the carb by over filling the float bowls. After a lot of experimenting and testing, I've found that a 14mm float height provides improved response and less stumbling than the RB recommended 15mm height and zero flooding. True this setting will cause the carb to run slightly richer (due to the fact that the emulsion tube is more submerged in fuel) but I think that this richer mixture accounts for the smoother operation and near zero stumbling while cornering to the right. Going much beyond 14mm results in even smoother operation, but the instances of flooding after hard cornering or sudden braking also increase.

metalliman 09-06-02 09:10 AM

Thanks for the specs, I'll have to re-measure the float levels today. As for rebuilding the carb, the kit is in the mail, as is my "Dellorto and Weber" book that I ordered. By the way, where did you get those specs from?

SilverRocket 09-06-02 02:46 PM

From Mr. RXcetera himself:)

It is really important to make sure the carb is clean and in proper condition, has the proper RB spec jets and chokes (people put all kinds of weird things in there), all adjustments set properly (accel pump travel, float heights, pump jet holes lined up precisely), all parts of mixture adjust screws present and working as they should, etc.

You can't count on any of this stuff without making sure; I'm not sure what you've already done, but I'm thinking you might open it up to discover things are not as they should be, and that rebuild kit and maybe a few more parts will cure your problem. Also, that website is a key resource; it's got all the RB jet sizes and instructions on how to make key adjustments. I know that when working on my Dell, it has been a very useful resource.


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